Exam 3 - Business Statistics - Fall 2007 | BMGT 230, Exams of Business Statistics

Download Exam 3 - Business Statistics - Fall 2007 | BMGT 230 and more Exams Business Statistics in PDF only on Docsity! Business Statistics, BMGT230 Spring 2007 Studer-Ellis Examination 3 16 April 2007 COPY Z Please provide the information requested below and on the next page SHOW all relevant work When necessary, carry values out to at least three (3) decimal places. Good Luck! Last Name (print): Ls) m First Name (print): qq Course & Section: @mat2%o, 02.0% {63 BMGT 230 Spring 2007 Examination 3 COPY Z Print Name: Course & Section: deviation of $21.42. Thirty-three out of 100 times when a random sample omer tabs is selected, the 1z. Suppose the average checkout tab for all customers at a large plots ea $65.12 with a standard sample mean should exceed what value (FORMULA, with NUMBERS, REQUIRED)? (10 points) ee BD nea oe ae Pe (Rete ot Pe eens ois Fy Ue tL Ay, mate Py ip 42 404d HAS 2z, Crystal Presley, an executive with Time-Warner Music, has asked you to select a random sample of months and to construct a 99% confidence interval estimate for the mean number of CDs the company sells each month. After you show the confidence interval estimate to Crystal, she comments that the interval “seems too narrow.” If Crystal wants to keep the level of confidence at 99% and the values of the mean and standard deviation remain constant, what can you do to increase the width of the interval (FIVE or FEWER words, please!)? (5 points) decrease Sample 3z. To reduce waiting times for customers, an airline at BWI airport introduced the “snake system.” Under this system, all customers enter a single waiting line that winds back and forth in front of the counter. A customer who reaches the front of the line proceeds to the next free position. The 95% confidence interval for the long- run (or population) waiting time equaled 14.40795 to 19,59205. If the average waiting time before the “snake system” was introduced equaled 21 minutes, use the confidence interval to determine which of the following statements is true (CIRCLE the corresponding roman numeral; 5 points): i. The “snake system” dig not reduce the averdige waiting time. ii. The “snake system” did reduce the average waiting time, but the reduction was not statistically significant. (iii)The “snake system” did reduce the average waiting time, and the reduction was statistically significant. iv. One can not use a confidence interval to determine whether the “snake system” reduced the average waiting time significantly. 12z. An advertisement for Do-It-Now, Incorporated, a time management firm, guarantees that individuals who take the Corporation’s super time management seminar will increase their productivity or the Corporation will refund the seminar fee. Ineed Justice, a consumer rights activist, tested the claim in the advertisement. Inced selected 2't individuals and counted the number of times they performed a simple task in 60 minutes before and after taking the super time management seminar. a. Are the samples independent or dependent? (3 points) depend Qt Ne b. State the null and alternative hypotheses associated with the test Ineed conducted. (3 points) 4p Lpeforn E atin ‘hte, | before, # qtror c. If = 0.01, determine the critical value of the associated test statistic (include ALL relevant information and the sign or signs). (3 points) whet CAF Ot, APH ELEY d. If the calculated value of the associated test statistic equaled -3.578, state the decision regarding the null hypothesis. (3 points) 4 Ye Nak SCM ree et ayy ee 13z. The Sadie Ronald Corporation wants to compare four programs that train employees to perform a certain task. Thirty-two employees are randomly assigned to the training programs with eight employees in each program. At the end of the training period a test is conducted to determine how many times the employees can perform the task in one minute. The number of times the task is performed per minute is recorded for each employee as follows: ¥ Program 1 Program 2 Program 3 Program 4 12 21 12 4 14 22 13 5 10 19 14 7 9 25 12 9 12 22 17 8 15 23 11 10 il 20 14 6 13 24 il 7 Rig, MF 22. PZB fis 7 a. State the null and alternative hypotheses associated with the test. (3 points) He at pda pola Seay Hy at leaSr 2 mcans Curmare nny oh Oia b. Complete the associate ANOVA table below (6 points): SOURCE SUM OF SQUARES df. MEAN SQUARE Feat Between 936 Kelis S oid 78 Within thd mw = 2b Many EF Total sos wrt gt mene c. If a = 0.05, what is the critical value of the associated test statistic (include ALL relevant information)? (3 points} 2 2 Ay Fert (ar OBR, boas 4 : : use Of yy = 26 d. State your decision regarding the null hypothesis. (3 points) sel ony we Ae pet Feale 18 terqer Pere a. Peli e. If Tukey’s HSD (a = 0.05) equals 2.75, which specific training programs differ significantly from each other with respect to how many times employees can perform the task per minute? (4 points) aL 2 3 bal 4 6 Ge oo Pragwarn Ge Wefbors oe exten Mak 2, a & © yee uy 2 B iw me